Electrode steam boiler



ELECTRODE STEAM BOILER Filed April 13 1925 |v1vev1bor` Siegfried Kowallik,

by Hi8 Attofheg enemies new. es, iena UNTTED STATES entrenar ermee.

SIIEGFRIED KOWALIILIK, OF PANKOW, BERLIN, GERMANY, ASSIGNOR T GENERAL ELECTRIC COETPANY, A CORPORATION OF NEW YORK.

ELECTRODE STEAM BOJILER.

Application led. April 13, 1926, Serial No. 101,818, and in Germany April 30, 1925.

The present invention relates to electrode steam boilers, and more particularly to a means for removing from such boilers the salts and other impurities with which they gradually become charged in operation, and which tend to cause undesirable overloading by increasing the conductivity of the boiler liquid.

rlhe increased conductivity of the boiler l water is particularly noticeable in boilers various the boiler with a water conductivity on the average somewhat higher than that tor manner that overloading' beyond permissible which the boiler is designed. This in turn causes the regulation to become less sensitive, and causes the boiler to become overloaded.

The object ot the present invention is to provide an improved arrangement in an electrode boiler whereby the boiler is automatically drained of deposits and other conduc-tivity increasing impurities in such a limits is prevented, and good regulation permitted for various loads, thus obviating the disadvantages above mentioned.

in carrying out the object ot the invention, an electrode boiler having a regulator responsive to a certain operating condition, such as the pressure delivered by the boiler for controlling its output, is provided with F means in circuit with theelectrodes which is responsive to changes in current flow thereto, but which by connection with the regulator is rendered non-responsive to normal changes in current :dow occasioned by regulating operations ot the boiler while the conductivity of the boiler water or liquid remains below a certain predetermined limit.

'lhe current-responsive device is arranged to lcontrol a drain valve, or other suitable 5 drain means for the boiler, and operates to open said valve when the current ow to the electrodes includes an added current value for any regulating position,`over the normal value for that position, which added current value is set up by the presence ot' an undesiiably large proportion of salts and other eo conductivity increasing impurities in the boiler liquid. I

For a further consideration ot what is believed to be novel, and the invention, attention is now directed to the accompanying drawing, the description taken in connection therewith, and the appended claims.

ln the drawing, thel figure is a diagrammatical illustration, partly in section, ot an electrode boiler provided with an arrangement embodying the invention.

Referring to the drawing, 5 is an electrode boiler having spaced, insulated electrodes 7 and 8 suspended in a steam generating chamber 9, and arranged for three-phase alternating-current operation, although any suitable number and arrangement ot electrodes for either direct or alternating current operation may be provided. A. pertorated wall l0 separates the steam generating chamber from a feed water supply basin ll in the lower end ot the boiler.

Condensate or feed water is supplied to the boiler through a conduit l2, in which is located a normally open, handcontrol valve 13 and a valve la. rThe latter valve is controlled by a float 15 located within the supply basin ll. The iioat and valve serve as an automatic means for maintaining a constant supply of liquid in the supply basin. The tloat is shown in its normal position in which it holds the valve ll closed. As the level of the liquid in the supply basin falls, the loat follows and causes the valve le to open proportionately, thereby permitting the liquid level to be restored to normal.

The liquid in the supply basin is delivered to the electrode chamber 9 through a conduit 16, in which is located a pump i7. The pump in the present example operates preterably at constant speed, and causes the liquid to pass troni the supply basin to the electrode chamber. 'lhe liquid in the electrode chamber returns in part to the supply basin through the perforated wall 10, and in part is evaporated by the heat generated by the current flowing between the electrodes.

rThe rate of delivery by the pump may be regulated by any suitable means, and in the present example is regulated by a valve 18 lll@ increases and decreases slightly in response to decreases and increases in the demand for steam taken through the delivery conduit 20. rlhe pressure regulator moves valve 18 in response to the pressure changes to increase or decrease the depth ot immersion ct the electrodes, thereby increasing or decreasing the current flow to electrode 6, and correspondingly increasing or decreasing the boiler output. Such changes in current How are thus normal to the operation of the boiler, and Within the limits of its capacity. They are not caused by the accumulation of impurities in the boiler, but, since the solenoid is in thel Working circuit, such changes cause a varying current How therein. However, the tapswitch, by which the solenoid is controlled, is operated by the pressure regulator, as has been liereinbefore mentioned, and causes a4 greater number or" solenoid turns to be included in the circuit as the pressure increases; that is, as the piston 26 moves downwardly in response to the increased pressure accompanying a decreased demand upon the boiler. Likewise, the regulator operates the tap-switch to place a lesser number of solenoid turns in circuit as the pressure decreases; that is, as the piston 26 moves up- Wardly in response to the decreased pressure accompanying an increased demand upon the boiler.

lt Will thus be seen that the tap-switch by its operation, in conjunction With the pressure regulator, provides a compensating control for the solenoid. lt operates to cause the Working current taken by electrode 6, which is substantially the same as that taken by the other electrodes, to How through a varying number of turns in the solenoid, a greater number of turns being automatically provided when the current How decreases, and a lesser number of turns being automatically provided when the current flow increases. lln other Words, the tap-switch 24 by its operation, in conjunction with the pressure regulator, prevents the solenoid 23 -Irom operating in response to the normal changes in current flow as provided by the regulating operation of the boiler, and does this by automatically maintaining substantially a constant number of ampere turns in the solenoid for all conditions of operation of the` boiler. The strength of spring 34 is so adjusted that the core 32 does not respond to the normal ampere turn value of the solenoid, thereby preventing the solenoid from effecting a closure of the switch until a certain predetermined increase in the current flow above the normal regulated value is brought about by the presence of salts and'` other conductivity increasing impurities inthe boiler liquid.

Stated in another Way, the solenoid and tap-switch provide an adjustable currentresponsive means in connection With the Working or electrode circuit of the boiler, the operating setting of Which means is represented by a certain Working or electrode current flow and Which setting, by connection With the regulator, is continually maintained above a point represented by the normal regulated value of the Working current, by a certain predetermined amount.

By normal regulated value ot' the current is meant the value of the working or electrode current as established by the regulating means of the boiler when the boiler is substantially free of conductivity increasing impurities.

An increase in the conductivity of the liquid, because of an accumulation of salts or other impurities, therefore, causes an increase in the ampere turn value oit the solenoid above normal for all conditions of regulation. ampere turns, the solenoid then causes the core 32 to move to close the circuit through contacts 35, thereby draining the boiler of the impurities through valve 39.

Solenoid 23, together With the drain valve which it controls, thus provides a means for draining the boiler of impurities in response to excessivev Working current to the electrode, While the tap-switch, in connection with the regulator, maintains the limit at Which said means operates, continually above the normal Working current by a cer- 'tain amount as said current varies through its regulating range.

As soon as the conductivity of the liquid is returned to normal, solenoid 23 is no longer energized sufficiently to hold the bridging contact in the closed position, and valve 39 is then permitted to close through opening of the circuit through solenoid 36. llhe drain valve 39 is provided with an outlet conduit 42 which leads` to any suitable drain, not shown.

The level of the liquid in the supply basin is automatically restored to normal during and following the drainage operation of' thel boiler by the lowering of the lloat controlling inlet valve 14 according to the operation hereinbefore described.

To indicate approximately the condition of operation of the boiler, that is, the steam pressure, a pointer 48 connected with the rod is arranged to move over a iXed scale 44. In the present example the pointer is provided in connection With the tapswitch 24. v Y

From the foregoing description, it will be seen that the boiler is provided with an arrangement which operates automatically to drain the boiler Whenever the conductivity of the liquid therein exceeds a certain predetermined value; that is, Whenever the boiler tends to draw from the supply mains an excessive current caused by the presence of salts or other conductivity increasing imln response to the increased lll purities l permito v 7 1 the ooi.l to in normal manner throughout its 'lull regulating range without interruption.

`lllfhile the invention nas oeen described and illustrated in connection with simple electrode boiler provided vvith. pressure the boiler connected with said firstnamed' means for preventing operation thereot While said current flow is Within normal Working limits.

2. rlFhe combination with an electrode boiler having means for regulating the tlow oi Working current thereto, ot' means responsive to the flow ot Working current tor draining the boiler, said current-responsive means being adjustable in its response to the value ofthe Working current, and means providing a connection between the regulating means and said current-responsive means whereby it is adjusted by said regulating means.

' 3. An electrode boiler having a regulator "which controls the vvorling current, charac terized by the tact that the boiler is provided with a deposit draining means which is controlled by the Working current and operated by a certain excess over any regulated value of said Working current.

fl. rll`he combination with an electrode boiler, of means for automatically draining said boiler, said means comprising a currentresponsive devioe im circuit with an electrode, means responsive to the boiler` pressure connected with the current-responsive device to control the operation of the same, and a valve operated by said current-responsive device.

5. The combination with an electrode boiler, of a pressure regulator connected therewith, a solenoid coil, a tap-switch for said solenoid coil connected with said pres- .solenoid controlled by said str/itch, means :orm-

coil, a drai` i the solenoid coil and he boiler electrodes.

ion with electrode mulator controlling the current tlovv to its odes, et an adjustable current-responsive .,levice operated by the electrode current, d means for the boiler controlled by the current-responsive device, and means controlled by the regulator for adjusting the currentresponsive device for response to the electrode current above a certain predetermined value above the normal regulated value of the electrode current.

'l'. The combination with an electrode boiler, ot' a regulator connected therewith :tor controlling the electrode current, in response to an operating condition ot the boiler, a drain valve tor the boiler., means responsive to the electrode current for opening said drain valve, said means being adjustable to respond to different values of electrode current, and means providing con nection between the regulator and said current-responsive means for adjusting the latter in accordance with the operation oli the regulator for response to a current value above the normal regulated electrode current.

8. The combination with electrode boiler having a regulated electrode current, ot means connected therewith for draining the boiler oit impurities in response t a certain predetermined increase in the electrode current above the normal regulated value thereof.

l). rlhe combination4 vvith an electrode boiler having a vvorlring circuit, oil an adjustable current-responsive device connected With said Working circuit, said device having an operating setting represented by a certain Working current, means for draining the boiler connected with said device 'to be operated thereby, and means connected with the device for maintaining' its operating setting above the normal regulated value or" the Working current by a certain predetermined amount.

lln Witness whereof, l have hereunto set my hand this 23rd day of March, 1926.

smornrnn novi/attire ing a circuit throi' tap-switcliA o The combinL boiler having a r- 

